INFO: task syz.1.1480:9405 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.1480      state:D stack:26536 pid:9405  tgid:9404  ppid:5597   task_flags:0x480140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 schedule+0x164/0x2b0
 blk_mq_freeze_queue_wait+0x101/0x180
 queue_limits_commit_update_frozen+0x55/0xd0
 nbd_set_size+0x4c5/0x7d0
 nbd_genl_reconfigure+0x7e1/0x1040
 genl_family_rcv_msg_doit+0x233/0x340
 genl_rcv_msg+0x614/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x7bd/0x940
 netlink_sendmsg+0x813/0xb40
 sock_sendmsg_nosec+0x13a/0x180
 ____sys_sendmsg+0x54e/0x850
 ___sys_sendmsg+0x2a5/0x360
 __x64_sys_sendmsg+0x1b1/0x290
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f18d1d9e159
RSP: 002b:00007f18d2d46028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f18d2025fa0 RCX: 00007f18d1d9e159
RDX: 0000000000000044 RSI: 0000200000000280 RDI: 0000000000000004
RBP: 00007f18d1e3506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f18d2026038 R14: 00007f18d2025fa0 R15: 00007ffc3373abf8
 </TASK>
INFO: task syz.4.1486:9417 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.1486      state:D stack:27624 pid:9417  tgid:9416  ppid:7743   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x7bd/0x940
 netlink_sendmsg+0x813/0xb40
 sock_sendmsg_nosec+0x13a/0x180
 __sys_sendto+0x408/0x5a0
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5ad615e98e
RSP: 002b:00007f5ad43f4e88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f5ad43f66c0 RCX: 00007f5ad615e98e
RDX: 0000000000000024 RSI: 00007f5ad43f5000 RDI: 0000000000000004
RBP: 0000000000000000 R08: 00007f5ad43f4f04 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 00007f5ad43f4f58 R14: 00007f5ad43f5000 R15: 0000000000000000
 </TASK>
INFO: task syz.0.1488:9423 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.1488      state:D stack:27872 pid:9423  tgid:9422  ppid:5593   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x7bd/0x940
 netlink_sendmsg+0x813/0xb40
 sock_sendmsg_nosec+0x13a/0x180
 __sys_sendto+0x408/0x5a0
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd13915e98e
RSP: 002b:00007fd13a098e88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007fd13a09a6c0 RCX: 00007fd13915e98e
RDX: 0000000000000020 RSI: 00007fd13a099000 RDI: 0000000000000006
RBP: 0000000000000000 R08: 00007fd13a098f04 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006
R13: 00007fd13a098f58 R14: 00007fd13a099000 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:9426 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:23280 pid:9426  tgid:9426  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x7bd/0x940
 netlink_sendmsg+0x813/0xb40
 sock_sendmsg_nosec+0x13a/0x180
 __sys_sendto+0x408/0x5a0
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbd5855e98e
RSP: 002b:00007ffcbc593a28 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00005555718b5500 RCX: 00007fbd5855e98e
RDX: 0000000000000020 RSI: 00007fbd59354670 RDI: 0000000000000005
RBP: 0000000000000001 R08: 00007ffcbc593aa4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005
R13: 00007ffcbc593af8 R14: 00007fbd59354670 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:9445 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:23144 pid:9445  tgid:9445  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x7bd/0x940
 netlink_sendmsg+0x813/0xb40
 sock_sendmsg_nosec+0x13a/0x180
 __sys_sendto+0x408/0x5a0
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fefaef5e98e
RSP: 002b:00007ffe90027a48 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000555564ed8500 RCX: 00007fefaef5e98e
RDX: 0000000000000020 RSI: 00007fefafd54670 RDI: 0000000000000005
RBP: 0000000000000001 R08: 00007ffe90027ac4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005
R13: 00007ffe90027b18 R14: 00007fefafd54670 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:9447 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:22728 pid:9447  tgid:9447  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17db/0x58f0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7c1/0x1550
 genl_rcv_msg+0x10b/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x7bd/0x940
 netlink_sendmsg+0x813/0xb40
 sock_sendmsg_nosec+0x13a/0x180
 __sys_sendto+0x408/0x5a0
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4828b5e98e
RSP: 002b:00007ffeff8de598 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000555560784500 RCX: 00007f4828b5e98e
RDX: 0000000000000020 RSI: 00007f4829954670 RDI: 0000000000000005
RBP: 0000000000000001 R08: 00007ffeff8de614 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005
R13: 00007ffeff8de668 R14: 00007f4829954670 R15: 0000000000000000
 </TASK>

Showing all locks held in the system:
locks held by pr/ttyS0/16: 2, last CPU#0:
 #0: ffffffff8ec362b8 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60
 #1: ffffffff9ad31098 (&port_lock_key){-...}-{3:3}, at: univ8250_console_device_lock+0x67/0xc0
locks held by khungtaskd/35: 1, last CPU#1:
 #0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
locks held by getty/5417: 2, on CPU#0:
 #0: ffff888174bdb0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034762e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
locks held by udevd/5604: 1, on CPU#1:
 #0: ffff88810a410350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70
locks held by syz.1.1480/9405: 6, on CPU#1:
 #0: ffffffff902c1ae8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c1920 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
 #2: ffff88810a4b0260 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_genl_reconfigure+0x4a6/0x1040
 #3: ffff88810a4bbe78 (&q->limits_lock){+.+.}-{4:4}, at: nbd_set_size+0x284/0x7d0
 #4: ffff88810a4bb840 (&q->q_usage_counter(io)#50){++++}-{0:0}, at: queue_limits_commit_update_frozen+0x55/0xd0
 #5: ffff88810a4bb878 (&q->q_usage_counter(queue)#34){+.+.}-{0:0}, at: queue_limits_commit_update_frozen+0x55/0xd0
locks held by syz.4.1486/9417: 2, on CPU#1:
 #0: ffffffff902c1ae8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c1920 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz.0.1488/9423: 2, on CPU#0:
 #0: ffffffff902c1ae8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c1920 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/9426: 2, on CPU#0:
 #0: ffffffff902c1ae8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c1920 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/9445: 2, on CPU#0:
 #0: ffffffff902c1ae8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c1920 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/9447: 2, on CPU#0:
 #0: ffffffff902c1ae8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c1920 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/9481: 2, on CPU#1:
 #0: ffffffff902c1ae8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c1920 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/9482: 2, on CPU#1:
 #0: ffffffff902c1ae8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c1920 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/9516: 2, on CPU#1:
 #0: ffffffff902c1ae8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c1920 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/9539: 2, on CPU#0:
 #0: ffffffff902c1ae8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c1920 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/9557: 2, on CPU#0:
 #0: ffffffff902c1ae8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c1920 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0
locks held by syz-executor/9575: 2, on CPU#0:
 #0: ffffffff902c1ae8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff902c1920 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 35 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 nmi_cpu_backtrace+0x274/0x2d0
 nmi_trigger_cpumask_backtrace+0x17d/0x390
 sys_info+0x135/0x170
 watchdog+0xfd7/0x1030
 kthread+0x38b/0x480
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 16 Comm: pr/ttyS0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:hrtick_schedule_exit+0x0/0x2b0
Code: 41 5e 41 5f 5d c3 cc cc cc cc cc e8 da c1 4c 0a 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <55> 41 57 41 56 41 55 41 54 53 49 89 fe 49 bd 00 00 00 00 00 fc ff
RSP: 0018:ffffc90000157a18 EFLAGS: 00000086
RAX: 0000000000000001 RBX: 1ffff9200002af68 RCX: 8000000000000002
RDX: ed000000000c003e RSI: ffffffff8e6fc1aa RDI: ffff88812103bac0
RBP: ffffc90000157c20 R08: ffff888102ed8007 R09: 1ffff110205db000
R10: dffffc0000000000 R11: ffffed10205db001 R12: ffff888102ed87e8
R13: dffffc0000000000 R14: ffff888102ed8000 R15: ffff88812103bac0
FS:  0000000000000000(0000) GS:ffff88818d6da000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5ae40b9d06 CR3: 000000016a2fc000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 __schedule+0x1dae/0x58f0
 preempt_schedule_common+0x7f/0xd0
 preempt_schedule_thunk+0x16/0x40
 _raw_spin_unlock_irqrestore+0x76/0x80
 nbcon_kthread_func+0x6c4/0x880
 kthread+0x38b/0x480
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
